On Tue, 5 Nov 2024 14:20:32 GMT, Per Minborg <pminb...@openjdk.org> wrote:
>>> Also, don't we already check the alignment before when calling
>>> `checkMemberOffset`? Why is it checked again here?
>>
>> Good catch.
>
>> What happens here if an element is already aligned, and `padding.byteSize()
>> == element.byteAlignment()`? e.g.
>> `MemoryLayout.structLayout(MemoryLayout.paddingLayout(4),
>> ValueLayout.JAVA_INT)`?
>
> This is an error that existed before this PR. On the main branch:
>
>
> @Test
> public void alignedByInitialPadding() {
> Linker linker = Linker.nativeLinker();
> var struct = MemoryLayout.structLayout(
> MemoryLayout.paddingLayout(Integer.BYTES),
> JAVA_INT);
> var fd = FunctionDescriptor.of(struct, struct, struct);
> linker.downcallHandle(fd);
> }
>
>
> would produce:
>
>
> test TestLinker.alignedByInitialPadding(): failure
> java.lang.IllegalArgumentException: Member layout 'i4', of '[x4i4]' found at
> unexpected offset: 4 != 0
> at
> java.base/jdk.internal.foreign.abi.AbstractLinker.checkMemberOffset(AbstractLinker.java:235)
> at
> java.base/jdk.internal.foreign.abi.AbstractLinker.checkLayoutRecursive(AbstractLinker.java:195)
> at
> java.base/jdk.internal.foreign.abi.AbstractLinker.checkLayout(AbstractLinker.java:176)
> at java.base/java.util.Optional.ifPresent(Optional.java:178)
> at
> java.base/jdk.internal.foreign.abi.AbstractLinker.checkLayouts(AbstractLinker.java:167)
> at
> java.base/jdk.internal.foreign.abi.AbstractLinker.downcallHandle0(AbstractLinker.java:98)
> at
> java.base/jdk.internal.foreign.abi.AbstractLinker.downcallHandle(AbstractLinker.java:92)
> at TestLinker.alignedByInitialPadding(TestLinker.java:160)
> at
> java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
I've raised a separate issue for this:
https://bugs.openjdk.org/browse/JDK-8343620
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/21041#discussion_r1829445374
